Heating pad systems, such as for patient warming applications

ABSTRACT

A heating pad system useable in one embodiment for warming a person on a support structure. In this embodiment, the heating pad system comprises an upper foam pad, a lower foam pad, and a thermal-electric heating element sandwiched between the upper and lower foam pads. A form-fitting waterproof cover encloses at least a portion of the upper and lower foam pads and the thermal-electric heating element. In one aspect of this embodiment, the heating pad system includes a power unit for providing electrical power to the thermal-electric heating element, the power unit including a control panel having at least one temperature selector, the temperature selector for selecting at least one heating pad temperature.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/212,380, filed Jun. 14, 2000, currently pending andincorporated herein by reference.

TECHNICAL FIELD

[0002] Embodiments described herein related generally to heating padsystems, such as heating pad systems useable for warming patients duringambulance transport or hospital procedures.

BACKGROUND

[0003] Patient warming is a significant concern in many medicalsituations. In emergency rooms, for example, many of the trauma patientsadmitted are hypothermic. If their hypothermia is not addressed, thesepatients can go into shock. Similarly, in hospitals, some adult patientswill experience hypothermia during or after surgery. If prolonged, thedetrimental physiological consequences of this hypothermia represents asignificant risk to these surgical patients.

[0004] Hypothermia reduces the blood flow to the appendages of the bodyin order to protect the vital organs. It is a natural defense mechanismthat can only be treated by warming the patient. Studies have shown thatsuch hypothermia may be related to the development of seriouspostoperative complications, such as impaired platelet function andincreased blood loss, resulting in heightened transfusion requirements.

[0005] Conventional methods for preventing intraoperative temperaturedecline in surgical patients include pre-warming a blanket using ablanket warming device and then placing the warmed blanket over thepatient. A convection heating device is also available that blows heatedair through a duct into a nonwoven blanket placed over the patient. Thenonwoven blanket has channels for the heated air to circulate in and isdisposable, making cleaning unnecessary. Another product circulatesheated water through a blanket in a similar manner. This water filleddevice, however, is typically placed under the patient.

[0006] Known methods such as these for preventing temperature declineare often inefficient and ineffective, particularly in older patients.Convection heating devices, for example, have proven expensive becauseof the disposable nonwoven blankets, not to mention the energy andmaintenance requirements. The high temperatures of the heated air ductin close proximity to anesthetized patients has also raised concerns. Inaddition, like pre-warmed blankets placed over the patient, they warmthe patient inefficiently from above, which has the collateral negativeeffect of limiting clinical access to the patient from the topside. Boththe air and water devices require relatively large amounts of energy,noisy pumps, and significant maintenance in the clinical environment. Inlight of the shortcomings associated with conventional patient warmingdevices, a low maintenance patient warming device that efficiently warmsa patient to a desired temperature, uses little energy, avoids hightemperatures, and overcomes other problems would be desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is an isometric view of a heating pad system in accordancewith an embodiment of the invention.

[0008]FIG. 2 is an isometric view of a heating pad system in accordancewith another embodiment of the invention.

[0009]FIG. 3 is an isometric view of a heating pad system in accordancewith yet another embodiment of the invention.

[0010]FIG. 4 is an enlarged schematic side cross-sectional view of aheating pad taken substantially along line 4-4 of FIG. 1 in accordancewith an embodiment of the invention.

[0011]FIG. 5 is a schematic top cross-sectional view of a heating padtaken substantially along line 5-5 of FIG. 1 in accordance with anembodiment of the invention.

[0012]FIG. 6 is an enlarged schematic cross-sectional view of a sealedconnector taken substantially along line 6-6 of FIG. 5 in accordancewith an embodiment of the invention.

[0013]FIG. 7 is a schematic top view of a power unit control panel takensubstantially along line 7-7 of FIG. 1 in accordance with an embodimentof the invention.

[0014]FIG. 8 is a schematic side elevational view of a power unitcontrol panel taken substantially along line 8-8 of FIG. 3 in accordancewith an embodiment of the invention.

[0015]FIG. 9 is a schematic diagram of the power unit and heating pad ofthe heating pad system of FIG. 1 in accordance with an embodiment of theinvention.

[0016]FIG. 10 is a schematic diagram of the power unit and heating padof the heating pad system of FIG. 2 in accordance with an embodiment ofthe invention.

[0017]FIG. 11 is a schematic diagram of the power unit and heating padof the heating pad system of FIG. 3 in accordance with an embodiment ofthe invention.

[0018]FIG. 12 is an isometric view of a heating pad system in accordancewith an alternate embodiment of the invention.

[0019]FIG. 13 is a schematic isometric view of a heating pad system thatincludes an alternating pressure pad in accordance with an embodiment ofthe invention.

[0020]FIG. 14 is an enlarged schematic side cross-sectional view of aheating pad that includes an alternating pressure pad takensubstantially along line 14-14 of FIG. 13 in accordance with anembodiment of the invention.

[0021] In the drawings, the same reference numbers identify identical orsubstantially similar elements or acts. To easily identify thediscussion of any particular element or act, the most significant digitor digits in a reference number refer to the Figure number in which thatelement is first introduced (e.g., element 1104 is first introduced anddiscussed with respect to FIG. 11).

DETAILED DESCRIPTION

[0022] The following disclosure describes heating pad systems useablefor personal warming in a number of different settings. In oneembodiment, a heating pad system includes a heating pad that can be usedfor warming patients during various hospital procedures. For example,the heating pad of this embodiment can be used to warm a patient duringambulance or gurney transport, during operating room procedures, orduring post-operative recuperation. In another embodiment, a heating padsystem includes two heating pads hingedly connected together that can bepositioned on the seat and back portions of a chair or other seatingdevice to warm a person situated on the seating device. The heated padsof this embodiment may find particular utility warming sitting patientsundergoing kidney dialysis treatment whose body temperatures tend todrop as a result of cooled blood reentering their bodies.

[0023] Many specific details of certain embodiments of the invention areset forth in the following description and figures to provide a thoroughunderstanding of, and an enabling description for, such embodiments. Oneof ordinary skill in the relevant art, however, will understand that thepresent invention may have additional embodiments, or that the inventionmay be practiced without several of the details described in thefollowing disclosure. In other instances, structures and functions thatare well known to those of ordinary skill in the relevant art have notbeen shown or described in detail herein to avoid unnecessarilyobscuring the description of embodiments of the invention.

[0024]FIG. 1 is an isometric view of a heating pad system 100 inaccordance with an embodiment of the invention. The heating pad system100 of the illustrated embodiment is an operating room (OR) tableheating pad system that includes a rectangular-shaped heating pad 110positioned on a stationary support structure 102, such as a conventionalOR table. The heating pad system 100 also includes a power unit 120 thatis freestanding and provides electrical power to, and receivestemperature data from, the heating pad 110 through a utility cord 130.In alternate embodiments, the power unit is secured to or integral withthe OR table.

[0025] In one aspect of this embodiment, the heating pad 110 iscomprised of an upper pressure relief foam pad 140, a lower pressurerelief foam pad 142, and a heating element 150 sandwiched therebetween.The upper and lower foam pads 140 and 142 and the heating element 150are enclosed within a form-fitting waterproof and antimicrobial cover112 that seals the foam against moisture and other contaminants. In theillustrated embodiment, the cover 112 includes a top portion 111 and abottom portion 113 that are joined together along a pad perimeter 115with welded or sealed seams to prevent fluid ingress and contamination.In another aspect of this embodiment, a sealable closing device 180,such as a spiral zipper, can be provided toward one end of the heatingpad 110 to allow access to the interior of the cover 112 for removal ormaintenance of the foam pads 140 and 142 or the heating element 150. Inan alternate embodiment, this closing device can be omitted and theheating pad 110 can be a closed unit. The heating pad 110 is vented inone embodiment through a vent tube 190 that sealably passes from theinterior of the cover 112 through a sealed connector 114 located towardone end of the heating pad 110. The vent tube 190 is incorporated intothe utility cord 130 and vents into the power unit 120. In an alternateembodiment, the vent tube 190 can be omitted and a vent filter can beincorporated into the cover 112 for venting the heating pad 110.

[0026] The electrical power for the heating element 150 enters the cover112 through the sealed connector 114. In one aspect of this embodiment,the sealed connector 114 is a tortuous-path connector that preventsingress of fluids and other contaminants inside the cover 112 byproviding a tortuous path that fluids and contaminants cannot breach. Areceptacle 126 connects the utility cord 130 to the power unit 120. Inanother aspect of this embodiment, the receptacle 126 is a sealedlocking DIN connector for preventing accidental disconnection of theutility cord 130 from the power unit 120. In other embodiments, otherconnectors, such as nonlocking connectors, can be used, or alternativelythe utility cord 130 can simply be hard-wired into the power unit 120.

[0027] The power unit 120 has a control panel 122 that includestemperature controls and information displays for the heating pad system100. In one aspect of this embodiment, the control panel 122 is atop-facing control panel that provides a horizontal interface that canbe easily seen and reached by hospital personnel working around the ORtable. The free-standing power unit 120 also includes a plurality ofcasters 128 rotatably attached to its underside for mobility. Thismobility enables the power unit 120 to be neatly stowed underneath anoverhanging portion 104 of the stationary support structure 102 to avoidinterference with hospital personnel (not shown) working around thestationary support structure. A retractable power cord 124 is includedon the power unit 120 for connecting the power unit to an external powersource, such as an AC outlet in the OR facility. In one aspect of thisembodiment, the retractable power cord 124 includes a three-prong plug125, such as a standard hospital grade NEMA 15 three-prong plug, formaking the connection to the external power source.

[0028] The heating pad system 100 can be used in accordance with anembodiment of the invention to provide efficient warmth and uniformlydistributed support to a patient (not shown) situated on the heating pad110 during an OR procedure. For example, after connecting the power unit120 to a suitable AC power source, hospital personnel can select anappropriate pad temperature on the control panel 122 based on the typeof procedure planned for the patient or the existing thermal conditionof the patient. The pad will accordingly come up to the selectedtemperature momentarily and begin to warm the patient. Alternatively,the patient can be placed on the heating pad 110 after the padtemperature is selected and the pad has come up to temperature.Accordingly, the heating pad 110 will generate heat as required tomaintain the surface of the pad at the selected temperature, therebyefficiently and comprehensively warming the patient to a favorabletemperature and reducing the likelihood of medical complications arisingfrom a drop in the patient's body temperature.

[0029] One advantage of the heating pad system 100 over conventionalwarming devices that warm the patient from the topside, such aspre-warmed topical blankets, is that the heat is more efficientlyapplied to the patient's body through the comprehensive foam supportprovided beneath the patient. Pre-warmed blankets placed over thepatient waste thermal energy that rises upward off these blankets awayfrom the patient. In contrast, the heating pad of the present inventionis positioned beneath the patient so that thermal energy rising off theheating pad will naturally be absorbed by the patient and not wasted. Afurther advantage of the present invention is that it affords hospitalpersonnel complete access to the patient without compromising patientwarmth.

[0030] The present invention also provides the advantage of reducing thelikelihood of bedsores. Bedsores, once thought only to occur after longperiods in a conventional bed, can also occur as a result of long ORprocedures on surfaces that lack the pressure relief foam of thisembodiment. On some conventional OR tables, the patient is oftensupported on localized pressure points. In contrast, the increasedcontact area provided by the pressure relief foam provides comprehensiveand uniformly distributed support to the patient, avoiding maladies suchas bedsores and enhancing the heat transfer properties between theheating pad and the patient.

[0031]FIG. 2 is an isometric view of a heating pad system 200 inaccordance with another embodiment of the invention. The heating padsystem 200 of the illustrated embodiment is a gurney heating pad systemthat includes a rectangular-shaped heating pad 210 positioned on top ofa mobile support structure 202, such as a conventional hospital gurney.In one aspect of this embodiment, the heating pad 210 is substantiallysimilar in both structure and function as the heating pad 110 shown inFIG. 1. The heating pad system 200 also includes a portable power unit220 for providing electrical power to, and receiving temperature datafrom, the heating pad 210 through a utility cord 230.

[0032] The power unit 220 includes one or more supports 221, such assupport straps, for releasably suspending the power unit neatly beneathan overhanging portion 204 of the mobile support structure 202 so thatit is out of the way of hospital personnel (not shown) moving orotherwise working around the mobile support structure. The power unit220 also includes dual control panels 222 located on opposite ends ofthe power unit. The control panels 222 of the illustrated embodiment areside-facing and include redundant left and right side temperaturecontrols and information displays for the heating pad 210.

[0033] In one aspect of this embodiment, the power unit 220 is aportable self-contained power unit that includes a power source, such asa storage battery. In one embodiment, this power source can be aninternal storage battery. In other embodiments, this power source can bea storage battery that is mounted to the outside of the power unit 220or is otherwise operably coupled to the power unit. This power sourceenables the power unit 220 to independently provide electrical power tothe heating pad 210 without connecting to an external AC power source,such as a facility outlet. This enables the heating pad system 200 toprovide comprehensive patient warmth regardless of the location of themobile support structure 202 and even when the mobile support structureis being moved between locations. The power unit 220 does include,however, a retractable power cord 224 that can optionally be used toaccess power from an external AC power source, such as a facilityoutlet, if desired to operate the heating pad 210 or to recharge theinternal power source.

[0034] In another aspect of this embodiment, the control panels 222include a display that indicates the status of the power unit's internalpower source. In one embodiment, this display is a visual warningdevice, such as a warning light, that flashes or otherwise changes itsappearance when the internal power source is approaching a pre-selectedpower level that may compromise the continued performance of the heatingpad 210. In another embodiment, this display is a digital display thatgraphically indicates the amount of time left on the internal powersource in hours. In yet another embodiment, the control panels 222 caninclude an audio warning device, such as a buzzer, that sounds when theinternal power source is approaching a pre-selected power level. In oneaspect of this embodiment, the audio warning device can provide two ormore different sounds, for example a high note and a low note, tosignify different levels of stored internal power. The low note cancorrespond to a moderate depletion of internal power, while the highnote can be reserved for a significant depletion of internal power.

[0035] The heating pad system 200 can be used in accordance with anembodiment of the invention to efficiently warm a patient (not shown)while situated on the heating pad 210 on a gurney or other similardevice. For example, a trauma patient entering an emergency room, or ahospital patient being transported from a hospital room to an operatingroom, may spend a considerable amount of time on a gurney prior to, orin lieu of, placement on a conventional OR table. In this situation, thepatient can be placed on the beating pad system 200 and hospitalpersonnel (not shown) can select an appropriate heating pad temperatureon one of the control panels 222. The heating pad 210 will then warm thepatient at this selected temperature during the entire period thepatient resides on the heating pad, whether for a short period duringrelocation or a relatively long period during surgery.

[0036] The heating pad system 200 provides the advantage of employingthe self-contained power unit 220 that enables continuous patientwarming even though the heating pad system 200 may not be near an ACoutlet. The heating pad system 200 provides the further advantage ofhaving dual control panels 222 facing in opposite directions. These dualcontrol panels 222 ensure that hospital personnel will always have readyvisual and tactile access to a control panel, even if one side of themobile support structure 202 is parked against a wall, as is often thecase in hospitals.

[0037]FIG. 3 is an isometric view of a heating pad system 300 inaccordance with yet another embodiment of the invention. The heating padsystem 300 of the illustrated embodiment is an ambulance gurney heatingpad system that includes a shaped heating pad 310 positioned on top of amobile support structure 302, such as a conventional ambulance gurney.The mobile support structure 302 has a collapsible undercarriage 303 forreducing the overall height of the mobile support structure. Thecollapsible undercarriage 303 is illustrated in FIG. 3 in a collapsedconfiguration, such as would be employed for transporting the mobilesupport structure 302 in a conventional ambulance where space istypically limited. In one aspect of this embodiment, the heating pad 310is substantially similar both in structure and function as the heatingpads 110 and 210 shown in FIGS. 1 and 2, respectively. Additionally, thefront of the heating pad 310 can have a tapered shape as shown if itenhances the utility of the heating pad in ambulance applications. Theheating pad system 300 also includes a portable power unit 320 forproviding electrical power to, and receiving temperature data from, theheating pad 310 through a utility cord 330.

[0038] In one aspect of this embodiment, the power unit 320 can beneatly and releasably stowed underneath an overhanging portion 304 ofthe mobile support structure 302 using one or more supports 321, such assupport straps. Stowing the power unit 320 avoids interference withparamedics or other personnel (not shown) moving or otherwise workingaround the mobile support structure. The power unit 320 can also behand-carried while moving the mobile support structure 302, or mountedto an adjacent structure during ambulance transport. Like the power unit220 of FIG. 2, the power unit 320 includes dual side-facing controlpanels 322 that afford easy visual and tactile access from either sideof the mobile support structure 302. In one aspect of this embodiment,the control panels 322 are substantially similar both in structure andfunction as the control panels 222 shown in FIG. 2; however, the controlpanels 322 of the illustrated embodiment can be lower profile toaccommodate the reduced space underneath the mobile support structure302.

[0039] In another aspect of this embodiment, the power unit 320 is aportable self-contained power unit that includes an internal powersource, such as an internal storage battery. This internal power sourceenables the power unit 320 to independently provide electrical power tothe heating pad 310 without connecting to an external AC power source,such as a facility outlet. This enables the heating pad system 300 toprovide comprehensive patient warmth regardless of location. The powerunit 320, however, also includes suitable attachments for connecting toexternal power sources when available and when desired to operate theheating pad 310 or recharge the internal power source. For example, thepower unit 320 includes a retractable power cord 324 having aconventional three-prong connector for connecting the power unit to asuitable AC electrical outlet. The power unit 320 also includes aretractable auxiliary power cord 326 for connecting to a suitable12-volt DC power source, such as a 12-volt DC electrical power systemtypically found in conventional ambulances and other vehicles.

[0040] In another aspect of this embodiment that is similar to the powerunit 220 discussed above, the control panels 322 include a display thatindicates the status of the power unit's internal power source. In oneembodiment, this display is a visual warning device, such as a warninglight, that flashes or otherwise changes its appearance when theinternal power source is approaching a pre-selected power level that maycompromise the continued performance of the heating pad 310. In anotherembodiment, this display is a digital display that graphically indicatesthe amount of time left on the internal power source in hours. In yetanother embodiment, the control panels 322 can include an audio warningdevice, such as a buzzer, that sounds when the internal power source isapproaching a pre-selected power level.

[0041] The heating pad system 300 can be used in accordance with anembodiment of the invention to provide warmth and uniformly distributedsupport to a patient (not shown) situated on the heating pad 310 duringtransport in a conventional ambulance (also not shown), or other medicalevacuation vehicle, such as a helicopter. For example, a trauma patientat an accident scene can be placed on the heating pad 310 for transportto an ambulance or other medical rescue vehicle. The undercarriage 303can be collapsed in this situation to make the heating pad system 300more like a conventional stretcher if this facilitates usage. Aparamedic or other user can then select an appropriate heating padtemperature on one of the control panels 322 based on the physiologicalneeds of the patient or the ambient temperature. The patient can then betransported on the heating pad system 300 to the ambulance or other suchvehicle. If the undercarriage 303 is not already collapsed to thelow-profile configuration, it can be collapsed before loading theheating pad system 300 into the vehicle. Once inside the vehicle, aparamedic or other user has a choice of power sources for the heatingpad 310. For example, the user could elect to keep powering the heatingpad 310 with the self-contained internal power source of the power unit320, or the user could elect to power the heating pad with an externalsource such as a suitable 12-volt DC outlet provided by the vehicle'selectrical system.

[0042]FIG. 4 is an enlarged schematic side cross-sectional view of theheating pad 110 taken substantially along line 4-4 of FIG. 1 inaccordance with an embodiment of the invention. As mentioned above, theheating pad 110 includes the upper foam pad 140, the lower foam pad 142,and the heating element 150 sandwiched therebetween. An adhesive 448,such as a nonflammable N-Propylbromide solvent-based nonlatex sprayglue, can be used between the upper and lower foam pads 140 and 142 tobond the foam pads together around a portion of the heating element 150.Power lines 431 and 432, extending from the sealed connector 114,complete the necessary electrical circuit between the power unit 120(not shown) and the heating element 150. A temperature control sensor460 and a temperature monitor sensor 462 are embedded in the upper foampad 140 adjacent to an upper surface 444 of the upper foam pad.Instrumentation lines 433 and 434 extending from the sealed connector114 complete the necessary electrical circuit between the power unit 120and the temperature control sensor 460. Instrumentation lines 435 and436 complete a similar circuit for the temperature monitor sensor 462.

[0043] In one aspect of this embodiment, the heating element 150 isenclosed in a sleeve 470. In one embodiment, the sleeve 470 has a topportion 471 comprised of a polyester, such as a 1.2 oz. per square yardnonwoven polyester, and a bottom portion 472 comprised of an insulationlayer, such as a 0.20 inch thick layer of silicone base foam, forreflecting heat upward toward the top surface 444. The bottom portion472 can optionally include a woven fiberglass fabric laminated to theside next to the heating element 150. The seam between the top andbottom portions 471 and 472 of the sleeve 470 is sealed, such as byultrasonic welding. In one aspect of this embodiment, the bottom portion472 can be comprised of BISCO BF-1000 or BISCO IF-200 foam sheetingprovided by the Rogers Corporation of Elk Grove, Ill.

[0044] A reflective or insulative material 473, such as heat-reflectingethylene film, aluminized Mylar, or a silicone foam layer, can also bepositioned adjacent to a lower surface 445 of the lower foam pad 142 forreflecting heat back into the heating pad 110 and to prevent it fromescaping and being wasted. Accordingly, the term “layer” as used herecould be a reflective coating applied to a surface of an existingstructure, or it could be a separate layer of material having reflectivequalities. An inner cover 490 neatly encloses the upper and lower foampads 140 and 142 between the foam pads and the cover 112. In oneembodiment, the inner cover 490 is a fire barrier material comprising aglass fiber strand encased in an acrylic sleeve. In one aspect of thisembodiment, the Integrity 30 product made of a Modacrylic fiber knit andprovided by Ventex, Inc. of Great Falls, Va., can be used for the innercover 490. In other embodiments, other materials, both flame resistantand non-flame resistant, can be used for the inner cover 490. In yetother embodiments, the inner cover 490 can be omitted.

[0045] The form-fitting cover 112 is shaped and sized to neatly enclosethe aforementioned components of the heating pad 110 and provide adurable exterior surface. In one embodiment, the sealed connector 114provides a functional path through the cover 112 while providing ahermetic and antimicrobial, or “environmental,” seal that preventsingress of harmful or contaminating substances. The utility cord 130sealably connects to the sealed connector 114 thereby connecting thepower unit 120 to the temperature sensors 460 and 462 and the heatingelement 150. As explained above, venting of the heating pad 110 isprovided by the vent tube 190 that passes through the sealed connector114 and allows the heating pad 110 to vent into the power unit 120 viathe utility cord 130.

[0046] In alternate embodiments, the cover 112 and the connector 114 canbe configured to provide less than a hermetic or antimicrobial sealaround the internal components of the heating pad 110. For example, inone alternate embodiment, the cover is a general purpose cover that,while generally covering at least a portion of the upper and lower foampads 140 and 142, it does not provide a waterproof, hermetic, orantimicrobial seal. In one aspect of this alternate embodiment, all or aportion of the heating pad may be disposable in the event the generalpurpose cover is breached by a contaminating substance, such asmoisture.

[0047] In one aspect of this embodiment, the upper foam pad 140 iscomprised of a “slow recovery” foam, such as viscoelastic foam having anapproximate indention force deflection (IFD) rating of 20 and a densityof 4 lb. per cubic foot. This foam is thermally conductive and selectedto efficiently transfer heat from the heating element 150 to a patient(not shown) positioned on top of the heating pad 110. This foam alsodemonstrates favorable compression characteristics resulting in evenlydistributed patient support. In other embodiments, the upper foam pad140 can be other viscoelastic foams having other IFD ratings and otherdensities. For example, the upper foam pad 140 can have an IFD rating ofbetween 10 and 100 and have a density of between 0.5-8 lb. per cubicfoot. In yet other embodiments, other foams can be selected for theupper foam pad 140 to satisfy other criteria. For example, an open cellfoam can be selected to enhance convective heat transfer properties ofthe upper foam pad 140 when this attribute is desired. Conversely, aclosed cell foam can be selected if it is desired to avoid fluidabsorption. In yet another embodiment, a gel can be used in place of theupper foam pad 140. The upper foam pad 140 of the illustrated embodimenthas a thickness dimension 446 of at least approximately 1.5 inches. Inother embodiments, the dimension 446 can be between 0.25 inch and 3inches, depending on the type of foam used, the heat output of theheating element 150, and the amount of compression desired. In yet otherembodiments, the dimension 446 can have other values.

[0048] In another aspect of this embodiment, the lower foam pad 142 iscomprised of a highly resiliency (HR) foam, such as 2.6 lb. per cubicfoot foam with an approximate IFD rating of 34. This foam is selectedbecause of its low thermal-conductive properties that insulate theheating element 150 and prevent heat from escaping through the bottom ofthe heating pad 110 and being wasted. In other embodiments, other foamscan be selected for the lower foam pad 142 where other attributes aredesired. For example, in one such embodiment, a foam having a density ofbetween 0.5 and 8 lb. per cubic foot and an IFD rating of between 10 and100 can be used. In yet other embodiments, a gel can be used for thelower foam pad 142. The lower foam pad 142 has a thickness dimension 447that in the illustrated embodiment is at least approximately 2.5 inches.In other embodiments, the dimension 447 can be between 0.1 inch and 4inches depending on the type of foam used and the amount of compressiondesired. In yet other embodiments, the dimension 447 can have othervalues, or the lower foam pad 142 can be omitted entirely. If the lowerfoam pad 142 is omitted in accordance with an embodiment, then supportfor a person (not shown) situated on the heating pad 110 is providedsolely by the upper foam pad 140, and the upper foam pad should be sizedaccordingly.

[0049] In another aspect of this embodiment, the heating element 450 isa thermal-electric plastic, such as a carbon-filled plastic havingcopper braids for conducting AC or DC electrical current. For example,the thermal-electric plastic sold under the trade nameStepWarmFloorEP30-3 or EP30-2 from Electro Plastics, Inc. of 4406 St.Vincent Ave., St. Louis, Mo. 63119, can be utilized in one embodiment.In other embodiments, other thermal-electric heating elements can beused. In yet other embodiments, heating elements other thanthermal-electric heating elements can be used. For example, heatingelements that circulate hot gas or hot water between the upper and lowerfoam pads 140 and 142 can be used in accordance with these embodiments.

[0050] The top portion 111 of the cover 112 of the illustratedembodiment is a urethane film laminated to a polyester/lycra knitsubstrate. This fabric features four-way stretch to prevent hammockingin the top surface and is also waterproof, flame-retardant,antimicrobial, and conductive to minimize the possibility of staticelectric discharges. The Penn Nyla company in England is one source forsuch material. The bottom portion 113 of the cover 112 of theillustrated embodiment is a conductive double-laminate vinyl withminimal stretch, such as provided by the Herculite Corporation. Whileexhibiting properties similar to the top portion 111, the bottom portion113 is more durable than the top portion. The top and bottom portions111 and 113 are constructed with welded sealed seams, such as byultrasonic welding, to prevent fluid ingress and contamination. Whilenot illustrated in FIG. 4, in alternate embodiments the top and bottomportions 111 and 113 can be joined together by a spiral zipper orsimilar attachment device. A separable cover such as this permits easyaccess to the internal components of the heating pad 110 for cleaning,repair, or replacement. In other embodiments, other mechanisms andmethods can be used to join together the top and bottom portions 111 and113 of the cover 112. For example, the top and bottom portions 111 and113 can comprise edge flaps in one embodiment that can be sealablyfolded together to provide a simple attachment mechanism.

[0051]FIG. 5 is a schematic top cross-sectional view of a heating pad110 taken substantially along line 5-5 of FIG. 1 in accordance with anembodiment of the invention. The heating pad 110 has a length dimension501 and a width dimension 502. In one aspect of this embodiment, thelength dimension 501 is approximately 80 inches and the width dimension502 is approximately 20 inches. In other embodiments, these dimensionscan have other values depending on the requirements of the particularapplication. For example, the width dimension 502 may be considerablylarger than 20 inches to accommodate bariatric patients. In otherapplications, the length dimension 501 may be substantially less than 80inches where, for example, only torso warming is desired. As will bereadily apparent to those of ordinary skill in the relevant art, aheating pad in accordance with the present invention could have manyshapes and sizes to meet the needs of a particular application. Round,curved, and multisegmented shapes, for example, are all possible andwell within the scope of the present disclosure. In addition, to theextent that there are “standard” shapes for OR or Gurney pads,embodiments can be provided in these standard shapes. For example, if auniversal stretcher pad is 24 inches wide by 76 inches long, then aheating pad in accordance with an embodiment can be provided with thesedimensions.

[0052] The heating element 150 has a length dimension 503 and a widthdimension 504. In one aspect of this embodiment, the length dimension503 is 60 inches and the width dimension 504 is 14 inches. In otherembodiments, the heating element can have other dimensions. In theillustrated embodiment, the heating element 150 is substantiallycentered relative to the dimensions of the heating pad 110. In otherembodiments, the heating element 150 can be positioned in otherlocations depending on the particular heating characteristics sought.

[0053] In the illustrated embodiment, the heating element 150 has threecopper braids 551, 552 and 553 extending longitudinally from one end ofthe heating element to the other. As is known, the copper braids 551-553generate heat through electrical resistance while drawing relatively lowcurrent. The carbon-filled plastic of the heating element 150 suspendsthe copper braids 551-553 and is electrically resistive such that whenan electrical charge is placed on adjacent copper braids, thecarbon-filled plastic completes the electrical circuit between the twobraids and generates heat, warming the heating element. One benefit ofusing carbon-filled plastic is that it is radiolucent. Thus, a patientcan be X-rayed while situated on the heating pad 110, thereby avoidingtime-consuming and potentially hazardous moving operations. Elongateholes 555 are positioned in equally spaced patterns in between thebraids 551 and 552, and 552 and 553, of the heating element 150 toenhance flexibility of the heating element. In alternate embodiments,heating elements with more or fewer copper braids, with copper braidsextending in different directions, and with more or fewer holes ofdifferent shapes and patterns can be used in a heating pad in accordancewith alternate embodiments of the present invention.

[0054] As best seen by reference to FIG. 5, the sealed connector 114 ispositioned to one side of the heating pad 110 away from a centerline 505to avoid a patient's head (not shown, but presumably located toward thecenterline) being in close proximity to the sealed connector. The powerline 431 extends from the sealed connector 114 and branches toelectrical leads 531 and 533 on the copper braids 551 and 553,respectively. The power line 432, in turn, extends from the sealedconnector 114 to the lead 532 on the copper braid 552. The power lines431 and 432 complete the necessary electrical circuit to the heatingelement 150. As explained above, the instrumentation lines 433 and 434extend from the sealed connector 114 to the temperature control sensor460. Similarly, the instrumentation lines 435 and 436 extend from thesealed connector 114 to the temperature monitor sensor 462. Thetemperature control sensor 460 and the temperature monitor sensor 462are positioned in the upper foam pad 440 to optimize their ability tomeasure the true temperature of the heating pad 110 adjacent to apatient (not shown) positioned on the pad. Consistent with thisobjective, in the illustrated embodiment the temperature sensors 460 and462 are positioned in the upper foam pad 140 approximately aligned withthe centerline 505. This placement is intended to position thetemperature sensors 460 and 462 in close proximity to the torso of apatient residing on the heating pad 110. In other embodiments, theplacement of the temperature sensors can vary as required by theparticular application.

[0055]FIG. 6 is an enlarged schematic cross-sectional view of the sealedconnector 114 taken substantially along line 6-6 of FIG. 5 in accordancewith an embodiment of the invention. The sealed connector 114 of theillustrated embodiment is continuously secured or bonded to the cover112 around an outer perimeter 115. In one embodiment, the sealedconnector 114 is a bayonet locking DIN international connector with agasket for providing liquid resistance. In one aspect of thisembodiment, the sealed connector 114 will be a five pin type. In anotheraspect of this embodiment, the vent tube 190 can be incorporated into oradjacent to the connector to vent the interior of the heating pad 110(not shown). Accordingly, the sealed connector 114 can provide ahermetic and antimicrobial seal between the inside and the outside ofthe heating pad 110. In other embodiments, the sealed connector 114 canutilize a conventional tortuous-path type seal.

[0056]FIG. 7 is a schematic top view of the control panel 122 takensubstantially along line 7-7 of FIG. 1 in accordance with an embodimentof the invention. Although the discussion that follows describes thecontrol panel 122, the control panels 222 and 322 are substantiallysimilar except as noted below. The control panel 122 includes an on/offswitch 770, a temperature display 771, a temperature selection console772, a power-loss warning light 774, and a circuit reset switch 776. Theon/off switch 770 of the illustrated embodiment is a typical hospitalgrade rocker switch; however, various other types of on/off switches canalso be used for this device. In an alternate embodiment, the on/offswitch 770 can be omitted. In this alternate embodiment, the heating pad110 begins warming to a selected temperature as soon as the power unit120 is plugged in to a suitable AC outlet. Because the heating pad 110requires little power, the omission of an on/off switch should notresult in an appreciable expense.

[0057] In one aspect of this embodiment, the temperature display 771 isa digital LED display that indicates the current pad temperature asmeasured by the temperature monitor sensor 462 (not shown). Thetemperature display 771 is shaped and sized to enhance its readabilityby personnel working around the heating pad system 100 (also not shown).The temperature selection console 772 includes a plurality of selectorbuttons 773 associated with different temperature settings. In theillustrated embodiment, the available temperatures range from 90° F. to100° F. in two-degree increments. As will be apparent to those ofordinary skill in the relevant art, other temperature ranges can beadopted depending on the requirements of the particular application. Thedesired temperature is selected by pressing the corresponding buttonafter the on/off switch 770 has been switched to the on position. Inanother embodiment, the temperature selection is automatically set to adefault temperature when the power unit is first turned on. In thisembodiment, the preset default temperature can be the lowest availablepad temperature.

[0058] In one embodiment, the power-loss warning light 774 provides anindication, such as by illuminating, when the power unit is on. Forexample, for those power units that do not have an internal powersource, such as the power unit 120 of FIG. 1, if the light is on, theunit is powered-up. On those power units that do have their own internalpower source, however, such as the power units 220 and 320 shown inFIGS. 2 and 3, the power-loss warning light 774 can, in one embodiment,flash or otherwise change its appearance to indicate when the internalpower source is approaching a level that may compromise the continuedperformance of the heating pad. This compromising level, in oneembodiment, can correspond to when only enough power remains in theinternal power source to operate the heating pad at its highesttemperature setting for one hour or less. In other embodiments asexplained above, other types of warning devices can be incorporated toalert the user of low power levels. One such device is an audio warningdevice. Another such device is an internal power level digital display,similar to the temperature display 771, that digitally displaysestimated available operating time remaining in hours.

[0059] The reset switch 776 is provided on the control panel 122 topermit a user to reset the power circuit after one or more safety fuseshave been tripped. As will be explained in greater detail below, thepower units 120, 220, and 320 of FIGS. 1-3, respectively, each include anumber of safety fuses to avoid electrically overloading theirrespective heating pads or their circuitry. Those of ordinary skill inthe relevant art will recognize that the control panel 122 can includeother features in addition to those shown in FIG. 7 without departingfrom the scope and intent of the present disclosure. For example,instead of having the temperature selection console 772 with a pluralityof selector buttons 773, the control panel could include a rotatabledial for selecting any temperature within a preselected range. Inanother embodiment, temperature selection could be accomplished using atouch screen having an up-arrow and a down-arrow. Any temperature withina preselected range could be selected in this embodiment by pressing thecorresponding up- or down-arrow to accordingly raise or lower the padtemperature.

[0060]FIG. 8 is a schematic side elevational view of the control panel322 taken substantially along line 8-8 of FIG. 3 in accordance with anembodiment of the invention. The control panel 322 of the illustratedembodiment is substantially similar to the control panels 122 and 222discussed above in accordance with FIG. 7. In one aspect of thisembodiment, however, the control panel 322 includes a reduced set ofdedicated temperature selector buttons 873 on a temperature selectionconsole 872. The reduction in available temperature settings allows alower profile control panel 322 that facilitates storage of the powerunit 320 under the mobile support structure 302 as shown in FIG. 3. Thisreduction in available temperatures may not impair the utility of theheating pad system 300 (FIG. 3) because fewer temperature selections maybe sufficient in patient transport applications. In alternateembodiments, the control panel 322 can include a wider range ofavailable temperatures. For example, the control panel 322 in onealternate embodiment could include all the temperatures included on thecontrol panels 122 and 222 discussed above in accordance with FIG. 7.

[0061]FIG. 9 is a schematic diagram of the power unit 120 and theheating pad 110 of FIG. 1 in accordance with an embodiment of theinvention. The power unit 120 includes the receptacle 126, fuse holders910 for fuses, a transformer 920, a relay 930, and the control panel122. The retractable power cord 124 is received in the receptacle 126 tointroduce power to the power unit 120. Power lines 931 and 932 extendfrom the receptacle 126 across the fuse holders 910 to the transformer920. Power lines 941 and 942 branch off the power lines 931 and 932,respectively, and continue beyond the transformer 920 to provide powerto the control panel 122. In one embodiment, the transformer 920converts standard AC voltage from a hospital facility outlet to 24 voltsDC. From the transformer 920 the power lines 931 and 932 proceed via arelay 930 to the heating element 150 in the heating pad 110. In oneaspect of this embodiment, in-line fuses 952 can be employed to avoidelectrical overload of the circuit. The relay 930 is controlled by theon/off switch 770 on the control panel 122. Accordingly, the on/offswitch must be in the “ON” position before power is allowed to flow fromthe transformer 920 to the heating element 150.

[0062] As explained above, the instrumentation lines 433 and 434 connectthe temperature control sensor 460 to the temperature selection console772. Accordingly, the temperature control sensor 460 measures atemperature in the heating pad 110 and transmits this information (forexample, as a varying voltage signal) to the temperature selectionconsole 772. If the measured temperature exceeds a selected temperature(for example, the varying voltage signal exceeds a preset voltage), thenthe temperature selection console 772 opens the relay 930, which cutsoff power to the heating element 150 thereby stopping heating of theheating pad 110 accordingly. Conversely, if the measured temperature isless than the selected temperature, then the temperature selectionconsole 772 maintains the relay 930 in the closed position to continuewarming the heating pad 110. As explained above, the temperature monitorsensor 462 is operably connected to the temperature display 771 on thecontrol panel 122 by instrumentation lines 435 and 436. Accordingly, thetemperature monitor sensor 462 measures a temperature of the heating pad110 and transmits this information to the temperature display 771 wherethe measured temperature is digitally displayed.

[0063]FIG. 10 is a schematic diagram of the power unit 220 and theheating pad 210 of FIG. 2 in accordance with an embodiment of theinvention. The power and instrumentation systems of the power unit 220are substantially similar to their counterparts in the power unit 120discussed above in accordance with FIG. 9. The power unit 220, however,also includes an internal power source 1010 and an associated transferrelay/charger module 1020. In one aspect of this embodiment, theinternal power source 1010 is a 24-volt DC battery pack. In otherembodiments, other power sources can be used. As explained above, theinternal power source 1010 enables the heating pad 210 to functionindependently of an external power source, allowing the heating padsystem 200 to move freely outside the range of facility AC electricaloutlets.

[0064] The on/off switch 770 controls the transfer relay/charger module1020 and the relay 1030. When the on/off switch 770 is in the “ON”position, the transfer relay/charger module 1020 permits power from theinternal power source to flow to the heating element 150 via the relay1030. If the retractable power cord 224 is connected to an externalpower source, such as a facility AC power outlet, then power willinstead flow from the external source to the heating element 150. Asexplained above, the internal power source 1010 is operably connected tothe power-loss warning light 774 to provide a visual indication of whenthe stored power is approaching a pre-selected low power level. If theretractable power cord 224 is connected to an external power source whenthe internal power source is below this pre-selected level, then thetransfer relay/charger module 1020 will direct power from the externalsource to the internal power source 1010 to recharge the internal powersource and maintain it at a pre-selected charged level.

[0065]FIG. 11 is a schematic diagram of the power unit 320 and theheating pad 310 of FIG. 3 in accordance with an embodiment of theinvention. The power unit 320 of the illustrated embodiment issubstantially similar to the power unit 220 described above inaccordance with FIG. 10, and includes an internal power source 1110. Thepower unit 320, however, also includes a receptacle 1126 for receivingthe auxiliary power cord 325, a DC converter 1140, a switching powersupply 1130, and a transfer relay 1122. The power unit 320 can utilizepower from an external 12-volt DC power source through the auxiliarypower cord 325, from an external AC power source through the retractablepower cord 324, or from the internal power source 1110. When utilizingexternal AC power or internal power, the power unit 320 functions in asubstantially similar manner as the power unit 220 described above inaccordance with FIG. 10. When utilizing external power from a 12-volt DCpower source, such as a 12-volt system on an ambulance vehicle, thepower is converted to 24-volt DC power at the DC converter 1140. Whenthe on/off switch 770 is switched to the “ON” position, the transferrelay 1122 permits power to flow from the DC converter 1140 to theheating pad 310 via a switching power supply 1130. The transfer relay1122 also directs power through a transfer relay/charger module 1120 forrecharging the internal power source 1110 if needed.

[0066] Referring to FIG. 5, those of ordinary skill in the relevant artwill understand that various other apparatuses and functions relating toascertaining, monitoring, and/or controlling the physical condition of apatient can be incorporated into the heating pad 110 in accordance withother embodiments of the invention. These other apparatuses can take theform of a built-in auxiliary device 580, or an external auxiliary device582. In addition, output from these devices, and control input to thesedevices, can be implemented, displayed and/or recorded on adisplay/record device 584. The display/record device 584 can, in oneembodiment, be connected to or otherwise incorporated with the powerunit (not shown) for receiving power and/or data from the power unit.

[0067] The built-in auxiliary device 580 in one embodiment can be aninstrumentation device, such as an additional temperature sensor, thatis incorporated into the beating pad 110 for determining the bodytemperature of a patient placed on the heating pad. In one aspect ofthis embodiment, the additional temperature sensor can be exposed on anupper surface of the cover 112. Similarly, the display/record device 584in one embodiment can be a suitable computer or microprocessor operablycoupled to the additional temperature sensor for displaying thetemperature on a suitable display. A data feedback loop between theadditional temperature sensor and the suitable computer can also beutilized to control the temperature of the heating pad 110 according tothe temperature of the patient as determined by the temperature sensor.

[0068] In another embodiment, the built-in auxiliary device 580 can beone or more moisture sensors incorporated into the cover 112 of theheating pad 110 to detect the presence of moisture on the surface of theheating pad. These moisture sensors can be connected to thedisplay/record device 584 to provide a signal if, and when, moisture ispresent on the cover 112. This signal can be used to alert hospitalpersonnel of unexpected leakage of medical or bodily fluids. In yetanother embodiment, the built-in auxiliary device 580 can be an array offorce sensors incorporated into the heating pad 110 so that the weightof a patient can be ascertained and monitored during the patient'speriod of care. A drop in body weight could be used to provide anindication of deteriorating physical condition. In yet anotherembodiment of the invention, the heating pad 110 can have a plurality ofalternating pressure portions that exert a varying massage-like pressureagainst a patient situated on the pad. Additionally, provisions forelectrically grounding a patient can be provided to avoid detrimentalelectrical interactions with the patient. For example, such groundingcould be used to avoid electrically shocking the patient during medicalprocedures involving a cauterizing pencil.

[0069] From the foregoing, it will be appreciated by those of ordinaryskill in the relevant art that various provisions for determining andmonitoring the vital signs of a patient situated on the heating pad 110can also be incorporated into the heating pad in accordance withadditional embodiments of the invention. For example, in one embodimentthe built-in auxiliary device 580 comprises exposed electrodes on thepad's upper surface that determines the heart rate of the patient. Inanother embodiment, the external auxiliary device 582 is comprised ofelectrode patches adhered to the patient's body to determine heart rate.In both these embodiments, the electrodes can be connected to thedisplay/record device 584, such as an EKG, to graphically display andmonitor the patient's heart rate. Similarly, blood pressure andrespiratory functions can also be determined by incorporating deviceswell-known in the relevant art into the heating pad 110. These devicescan be like the built-in auxiliary device 580, that are whollyintegrated within the heating pad system 100 and are used to passivelymonitor the patient; or, these devices can be like the externalauxiliary device 582, such as a blood pressure cuff, that appends fromthe heating pad and actively monitors the patient in the conventionalmanner.

[0070] In one aspect of these alternate embodiments, the heating padsystem 100 can also include appropriate interface connections so thatthe external auxiliary device 582 and the display/record device 584,which are not part of the heating pad system per se, can be interfacedwith the heating pad system. The display/record device 584 can be usedto receive signals or data from the measurement devices incorporatedinto the heating pad 110, or to send control input to the heatingelement or the other built-in or external auxiliary devices. The heatingpad system 100 can also be connected to the display/record device 584 sothat various measurements of the patient's conditions can be ascertainedand recorded over a period of time. In these alternate embodiments asdiscussed above, additional displays can be incorporated into thecontrol panel 122 to display the corresponding measurements and data toa user of the heating pad system 100, such as hospital personnel. Theforegoing discussion is equally applicable to the heating pad systems100, 200 and 300 of FIGS. 1-3, respectively.

[0071]FIG. 12 is an isometric view of a heating pad system 1200 inaccordance with an alternate embodiment of the invention. The heatingpad system 1200 of the illustrated embodiment is shaped and sized foruse on a conventional chair or other seating device, and includes afirst pad portion 1211 hingedly connected to a second pad portion 1213by a flexible coupling 1217. A utility cord 1230 connects the heatingpad system 1200 to a power source, and a temperature controller 1222controls the temperature of the first and second pad portions 1211 and1213. The first and second pad portions 1211 and 1213 are substantiallysimilar in both structure and function as the first and second padportions 111 and 113 of the heating pad system 100 shown in FIG. 1. Inone aspect of this embodiment, however, the heating pad system 1200 doesnot include temperature sensors. In other embodiments, temperaturesensors could be incorporated into the heating pad system 1200.

[0072] The heating pad system 1200 can be used in accordance withembodiments of the invention to provide personal warmth to a user seatedon the first pad portion 1211 with his or her back against the secondpad portion 1213. For example, in one embodiment the heating pad system1200 can be used in this manner to provide warmth to a person undergoingkidney dialysis treatment. As is known, body temperature decline oftenaccompanies kidney dialysis treatment as a result of treated bloodre-entering the body at a temperature below normal body temperature. Inother nonclinical embodiments, the heating pad system 1200 can be usedto provide warmth during outdoor recreational activities in coldweather, such as watching a sports game or riding a chair lift at a skiresort.

[0073]FIG. 13 is a schematic isometric view of a heating pad system 1300that includes an alternating pressure pad (APP) 1385 in accordance withan embodiment of the invention. The heating pad system 1300 of theillustrated embodiment is substantially similar to the heating padsystem 100 of FIG. 1, and includes a rectangular-shaped heating pad 1310that includes a heating element 1350 positioned beneath the APP 1385.The heating pad system 1310 is positioned on a stationary supportstructure 1302, such as a conventional OR table. The heating pad system1300 also includes a power unit 1320 that is substantially similar tothe power unit 120 of FIG. 1; however, the power unit 1320 also includesan APP pump unit 1382, such as a four-channel APP pump unit, forproviding pressurized air through ducting 1384 to the APP 1385. Theducting 1384 is incorporated into a utility cord 1330 that in all otherrespects is substantially similar to the utility cord 130 of FIG. 1.

[0074] The heating pad system 1300 functions in a substantially similarmanner as the heating pad system 100 of FIG. 1 with the exception of theAPP 1385. As is known, bedsores are a result of patients spendingextended periods of time in one position so that localized pressurepoints supporting their body weight lead to internal bruising. Thepossibility of bedsores occurring in this manner also exists foranesthetized patients during prolonged surgical procedures. APP pads areknown devices that seek to prevent bedsores by alternating pressure toadjacent portions, or channels, of a pressurized pad so as to alternatethe areas of support under a patient. In one embodiment, a four-channelAPP will alternate pressure to adjacent pressure channels once everyfive minutes. In other embodiments, other more or fewer channels orother time periods can be used. One advantage of the heating pad system1300 is that the integration of the APP into the heating pad system addsa further measure of prevention against bedsores that is not offered byconventional patient-warming devices.

[0075]FIG. 14 is an enlarged schematic side cross-sectional view of theheating pad 1310 taken substantially along line 14-14 of FIG. 13 inaccordance with an embodiment of the invention. As explained above, theheating pad 1310 is substantially similar to the heating pad 110 of FIG.1 (shown in cross-sectional view in FIG. 4) with some notable exceptionsresulting from the inclusion of the APP 1385. For example, the heatingpad 1310 includes a sealed connector 1414 that is substantially similarto the sealed connector 114 of FIG. 1. The sealed connector 1414,however, also sealably receives the ducting 1384 from the APP pump unit1382 (not shown). The ducting 1384 then extends from the sealedconnector 1414 to the APP 1385 to provide the necessary alternatingpressure pulses to the APP.

[0076] Because of the added thickness of the APP 1385, the heating pad1310 includes an upper foam pad 1440 and a lower foam pad 1442 that areconsiderably thinner than their counterparts 140 and 142, respectively,in the heating pad 110 of FIG. 1. For example, the upper foam pad 1440of this embodiment is approximately 0.38 inch thick, while the lowerfoam pad 1442 is approximately 0.50 inch thick. In another aspect ofthis embodiment, the upper foam pad 1440 can have an IFD of 20 while thelower foam pad has an IFD of 60. In other embodiments, other thicknessesand other IFDs can be used. The heating element 1350 and the othercomponents of the heating pad 1310 are substantially similar to theircounterparts in the heating pad 110 of FIG. 1, and further descriptionis accordingly not required here.

[0077] Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in a sense of “including,but not limited to.” Words using the singular or plural number alsoinclude the plural or singular number respectively. Additionally, thewords “herein,” “hereunder,” and words of similar import, when used inthis application, shall refer to this application as a whole and not toany particular portions of this application.

[0078] The above description of illustrated embodiments of the inventionis not intended to be exhaustive or to limit the invention to theprecise form disclosed. While specific embodiments of, and examples for,the invention are described herein for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. The teachings ofthe invention provided herein can be applied to other heating padsystems, not only to the embodiments described above. In addition, allof the above references and U.S. patents and applications areincorporated herein by reference.

[0079] While certain aspects of the invention are presented below incertain claim forms, the inventors contemplate the various aspects ofthe invention in any number of claim forms. Accordingly, the inventorsreserve the right to add additional claims after filing the applicationto pursue such additional claim forms for other aspects of theinvention.

[0080] From the foregoing, it will be appreciated that even thoughspecific embodiments of the invention have been described herein forpurposes of illustration, a myriad other configurations and uses existfor heating pad systems in accordance with the present disclosure. Itwill also be appreciated that various modifications may be made to theembodiments described herein without deviating from the spirit or scopeof the present disclosure. In general, in the following claims, theterms used should not be construed to limit the invention to thespecific embodiments disclosed in the specification and the claims, butshould be construed to include all heating pad systems that operateunder the claims. Accordingly, the invention is not limited by thedisclosure, but instead the scope of the invention is to be determinedentirely by the claims.

I claim:
 1. A heating pad system useable for warming a person on asupport structure, the heating pad system comprising: a thermal-electricheating element comprising one or more copper braids suspended in acarbon-filled plastic for conducting electricity; a viscoelastic foampad disposed adjacent to the thermal-electric heating element, theviscoelastic foam pad overlaying at least a portion of the heatingelement; a form-fitting waterproof cover enclosing at least a portion ofthe viscoelastic foam pad and the thermal-electric heating element, thethermal-electric heating element, the viscoelastic foam pad and thewaterproof cover comprising a heating pad positionable on the supportstructure; a sealed connector attached to the form-fitting waterproofcover, the sealed connector having an external interface, the sealedconnector providing an electrical connection between the externalinterface and the thermal-electric heating element; and a power unitconnectable to the external interface of the sealed connector forproviding electrical power to the thermal-electric heating element, thepower unit including a control panel having at least one temperatureselector, the temperature selector for selecting at least one heatingpad temperature.
 2. The heating pad system of claim 1 wherein theviscoelastic foam pad is an upper foam pad, the heating pad systemfurther comprising; a lower foam pad, the thermal-electric heatingelement being sandwiched between the upper foam pad and the lower foampad, the waterproof cover enclosing at least a portion of the upper foampad, the lower foam pad and the thermal-electric heating element,wherein the thermal-electric heating element, the upper and lower foampads, and the waterproof cover comprise the heating pad positionable onthe support structure.
 3. The heating pad system of claim 1 wherein theviscoelastic foam pad has an upper surface, and wherein the heating padsystem further comprises: a temperature sensor for measuring heating padtemperatures, wherein at least a portion of the temperature sensor ispositioned adjacent to the upper surface of the viscoelastic foam pad,the temperature sensor being operably connected to the power unit, andwherein the power unit includes a temperature control circuit coupled tothe temperature sensor to control electrical power provided to thethermal-electric heating element based on a selected heating padtemperature and a measured heating pad temperature.
 4. The heating padsystem of claim 1 wherein the viscoelastic foam pad has an upper surfaceand the power unit includes a temperature display for displayingmeasured heating pad temperatures, and wherein the heating pad systemfurther comprises: a temperature sensor for measuring heating padtemperatures, wherein at least a portion of the temperature sensor ispositioned adjacent to the upper surface of the viscoelastic foam pad,the temperature sensor being operably connected to the power unit forproviding measured heating pad temperatures to the temperature display.5. The heating pad system of claim 1 wherein the viscoelastic foam padis an upper foam pad having an upper surface, and wherein the heatingpad system further comprises: a heating element sleeve enclosing atleast a portion of the thermal-electric heating element, at least aportion of the heating element sleeve comprising an insulation layer; alower foam pad, the heating element sleeve and the thermal-electricheating element being sandwiched between the upper foam pad and thelower foam pad, the waterproof cover enclosing at least a portion of theupper foam pad, the lower foam pad, the heating element sleeve and thethermal-electric heating element, wherein the thermal-electric heatingelement, the heating element sleeve, the upper and lower foam pads, andthe waterproof cover comprise the heating pad positionable on thesupport structure; a first temperature sensor for measuring heating padtemperatures, wherein at least a portion of the first temperature sensoris positioned adjacent to the upper surface of the upper foam pad, thefirst temperature sensor being operably connected to the power unit, andwherein the power unit includes a temperature control circuit coupled tothe temperature sensor to control electrical power provided to thethermal-electric heating element based on a selected heating padtemperature and a measured heating pad temperature; and a secondtemperature sensor for measuring heating pad temperatures, wherein atleast a portion of the second temperature sensor is positioned adjacentto the upper surface of the upper foam pad, the second temperaturesensor being operably connected to the power unit, and wherein the powerunit includes a temperature display for displaying measured heating padtemperatures received from the second temperature sensor.
 6. A heatingpad system useable for warming a person on a support structure, theheating pad system comprising: a thermal-electric heating element; afoam pad positioned adjacent to the thermal-electric heating element,the foam pad covering at least a portion of the thermal-electric heatingelement, the thermal-electric heating element and the foam padcomprising a heating pad positionable on the support structure; and apower unit for providing electrical power to the thermal-electricheating element, the power unit including a control panel having atleast one temperature selector, the temperature selector for selectingat least one heating pad temperature.
 7. The heating pad system of claim6 wherein the foam pad is an upper foam pad, the heating pad systemfurther comprising: a lower foam pad, the thermal-electric heatingelement being sandwiched between the upper foam pad and the lower foampad, the thermal-electric heating element and the upper and lower foampads comprising the heating pad positionable on the support structure.8. The heating pad system of claim 6 wherein the support structure is anoperating room table.
 9. The heating pad system of claim 6 wherein theheating pad further comprises a waterproof and antimicrobial coverenclosing at least a portion of the foam pad and the thermal-electricheating element.
 10. The heating pad system of claim 6 wherein the foampad is a rectilinear upper foam pad, the heating pad system furthercomprising: a rectilinear lower foam pad, the heating element beingsandwiched between the rectilinear upper foam pad and the rectilinearlower foam pad, the thermal-electric heating element and the upper andlower rectilinear foam pads comprising the heating pad positionable onthe support structure.
 11. The heating pad system of claim 6 wherein thefoam pad is an upper foam pad, the heating pad system furthercomprising: a lower foam pad, the thermal-electric heating element beingsandwiched between the upper foam pad and the lower foam pad; awaterproof and antimicrobial cover enclosing at least a portion of theupper foam pad, the lower foam pad, and the thermal-electric heatingelement, wherein the thermal-electric heating element, the upper andlower foam pads, and the waterproof and antimicrobial cover comprise theheating pad positionable on the support structure; and a sealedconnector secured to the waterproof and antimicrobial cover, the powerunit providing electrical power to the thermal-electric heating elementvia a utility cord connected to the sealed connector.
 12. The heatingpad system of claim 6 wherein the foam pad is a first foam pad, whereinthe thermal-electric heating element is a first thermal-electric heatingelement, wherein the heating pad is a first pad portion, and wherein theheating pad system further comprises: a second thermal-electric heatingelement; a second foam pad positioned adjacent to the secondthermal-electric heating element, the second foam pad covering at leasta portion of the second thermal-electric heating element, the secondthermal-electric heating element and the second foam pad comprising asecond pad portion, wherein the power unit provides electrical power tothe first and second thermal-electric heating elements; and a flexiblecoupling, the flexible coupling providing a hinge-like connectionbetween the first pad portion and the second pad portion.
 13. Theheating pad system of claim 6 wherein the foam pad is an upper foam pad,the heating pad system further comprising: a lower foam pad, thethermal-electric heating element being sandwiched between the upper foampad and the lower foam pad; and a sleeve enclosing at least a portion ofthe thermal-electric heating element between the thermal-electricheating element and the upper and lower foam pads.
 14. The heating padsystem of claim 6 wherein the foam pad is an upper foam pad, the heatingpad system further comprising: a lower foam pad, the thermal-electricheating element being sandwiched between the upper foam pad and thelower foam pad; and a sleeve enclosing at least a portion of thethermal-electric heating element between the thermal-electric heatingelement and the upper and lower foam pads, wherein the sleeve has a topportion comprising a nonwoven polyester sheet and a bottom portioncomprising an insulation layer.
 15. The heating pad system of claim 6wherein the heating pad further comprises: a sheet of reflectivematerial positioned adjacent to the foam pad, the foam pad beingdisposed between the sheet of reflective material and thethermal-electric heating element.
 16. The heating pad system of claim 6wherein the heating pad further comprises: a reflective polyethylenematerial positioned adjacent to the foam pad, the foam pad beingdisposed between the reflective polyethylene material and thethermal-electric heating element.
 17. The heating pad system of claim 6wherein the foam pad has an upper surface, and wherein the heating padsystem further comprises: a temperature sensor for measuring heating padtemperatures, at least a portion of the temperature sensor beingpositioned adjacent to the upper surface of the foam pad, thetemperature sensor being operably connected to the power unit, the powerunit including a temperature control circuit coupled to the temperaturesensor to control electrical power provided to the thermal-electricheating element based on a selected heating pad temperature and ameasured heating pad temperature.
 18. The heating pad system of claim 6wherein the foam pad has an upper surface, and wherein the heating padsystem further comprises: a temperature sensor for measuring heating padtemperatures, at least a portion of the temperature sensor beingembedded in the foam pad adjacent to the upper surface of the foam pad,the temperature sensor being operably connected to the power unit, thepower unit including a temperature control circuit coupled to thetemperature sensor to control electrical power provided to thethermal-electric heating element based on a selected heating padtemperature and a measured heating pad temperature.
 19. The heating padsystem of claim 6 wherein the foam pad has an upper surface and thepower unit includes a temperature display for displaying measuredheating pad temperatures, and wherein the heating pad system furthercomprises: a temperature sensor for measuring heating pad temperatures,wherein at least a portion of the temperature sensor is positionedadjacent to the upper surface of the foam pad, the temperature sensorbeing operably connected to the power unit for providing measuredheating pad temperatures to the temperature display.
 20. The heating padsystem of claim 6 wherein the foam pad has an upper surface and thepower unit includes a temperature display for displaying measuredheating pad temperatures, and wherein the heating pad system furthercomprises: a temperature sensor for measuring heating pad temperatures,wherein at least a portion of the temperature sensor is embedded in thefoam pad adjacent to the upper surface of the foam pad, the temperaturesensor being operably connected to the power unit for providing measuredheating pad temperatures to the temperature display.
 21. The heating padsystem of claim 6 wherein the foam pad has an upper surface and thepower unit includes a digital numeric temperature display for displayingmeasured heating pad temperatures, and wherein the heating pad systemfurther comprises: a temperature sensor for measuring heating padtemperatures, wherein at least a portion of the temperature sensor ispositioned adjacent to the upper surface of the foam pad, thetemperature sensor being operably connected to the power unit forproviding measured heating pad temperatures to the temperature display.22. The heating pad system of claim 6 wherein the foam pad has an uppersurface and the power unit includes a temperature display for displayingmeasured heating pad temperatures, and wherein the heating pad systemfurther comprises: a first temperature sensor for measuring heating padtemperatures, at least a portion of the first temperature sensor beingpositioned adjacent to the upper surface of the foam pad, the firsttemperature sensor being operably connected to the power unit, the powerunit including a temperature control circuit coupled to the firsttemperature sensor to control electrical power provided to thethermal-electric heating element based on a selected heating padtemperature and a measured heating pad temperature; and a secondtemperature sensor for measuring heating pad temperatures, wherein atleast a portion of the second temperature sensor is positioned adjacentto the upper surface of the foam pad, the second temperature sensorbeing operably connected to the power unit for providing measuredheating pad temperatures to the temperature display.
 23. The heating padsystem of claim 6 wherein: the foam pad is comprised of a viscoelasticfoam; and the thermal-electric heating element is comprised of acarbon-filled plastic having one or more copper braids that receiveelectrical current for generating heat.
 24. The heating pad system ofclaim 6 wherein: the foam pad is an upper foam pad comprised of aviscoelastic foam; the thermal-electric heating element is comprised ofa carbon-filled plastic having one or more copper braids that receiveelectrical current for generating heat; and the heating pad systemfurther comprises a lower foam pad comprised of a high-resiliency foam,the thermal-electric heating element being sandwiched between the upperfoam pad and the lower foam pad.
 25. The heating pad system of claim 6wherein: the foam pad is an upper foam pad comprised of a slow-recoveryviscoelastic foam weighing at least approximately 4 lb. per cubic footand having an IFD rating of at least approximately 20; thethermal-electric heating element is comprised of a carbon-filled plastichaving one or more copper braids that receive electrical current forgenerating heat; and the heating pad system further comprises a lowerfoam pad comprised of a high-resiliency foam weighing at leastapproximately 2.6 lb. per cubic foot and having an IFD rating of atleast approximately 34, the thermal-electric heating element beingsandwiched between the upper foam pad and the lower foam pad.
 26. Theheating pad system of claim 6 wherein the thermal-electric heatingelement is comprised of one or more copper elements for generating heat.27. The heating pad system of claim 6 wherein the thermal-electricheating element is comprised of three longitudinally oriented copperbraids suspended in a carbon-filled plastic, the carbon-filled plasticbeing at least substantially radiolucent.
 28. The heating pad system ofclaim 6, further comprising: an alternating pressure pad positionedadjacent to the thermal-electric heating element, the alternatingpressure pad covering at least a portion of the thermal-electric heatingelement.
 29. The heating pad system of claim 6 wherein the foam pad isan upper foam pad, the heating pad system further comprising: a lowerfoam pad, the thermal-electric heating element being sandwiched betweenthe upper foam pad and the lower foam pad; and an alternating pressurepad interposed between the upper and lower foam pads.
 30. The heatingpad system of claim 6 further comprising: a display/record deviceconnected to the power unit for displaying a temperature of the personon the support structure; and an auxiliary temperature sensor connectedto the display/record device and being positionable adjacent to theperson on the support structure for determining the temperature of theperson and transmitting the determined temperature to the display/recorddevice.
 31. The heating pad system of claim 6 wherein the heating padfurther comprises a waterproof cover enclosing at least a portion of thefoam pad and the thermal-electric heating element, and furthercomprising: a display/record device connected to the power unit forproviding a signal indicating a presence of moisture on the waterproofcover; and an auxiliary moisture sensor disposed on the waterproof coverand connected to the display/record device for determining the presenceof moisture on the waterproof cover and transmitting the determinedpresence of moisture to the display/record device.
 32. The heating padsystem of claim 6 further comprising: a display/record device connectedto the power unit for displaying a blood pressure of the person on thesupport structure; and an auxiliary blood pressure cuff connected to thedisplay/record device and being releasably attachable to the person onthe support structure for determining the blood pressure of the personand transmitting the determined blood pressure to the display/recorddevice.
 33. The heating pad system of claim 6 further comprising: anauxiliary grounding device connected to the power unit and beingpositionable in contact with the person on the support structure toelectrically ground the person on the support structure.
 34. A heatingpad system useable for warming a person on a mobile support structure,the heating pad system comprising: a lower foam pad; an upper foam pad;a thermal-electric heating element sandwiched between the upper andlower foam pads, the thermal-electric heating element and the upper andlower foam pads comprising a heating pad positionable on the mobilesupport structure; and a power unit attachable to the mobile supportstructure, the power unit having a power source for providing electricalpower to the thermal-electric heating element, the power unit includinga control panel having at least one temperature selector, thetemperature selector for selecting at least one heating pad temperature.35. The heating pad system of claim 34 wherein the mobile supportstructure is a gurney.
 36. The heating pad system of claim 34 wherein:the control panel is a first control panel having a first set oftemperature selectors corresponding to a first set of selected heatingpad temperatures; and wherein the power unit further comprises a secondcontrol panel, the second control panel having a second set oftemperature selectors corresponding to a second set of selected heatingpad temperatures.
 37. The heating pad system of claim 34 wherein: thecontrol panel is a side-facing first control panel facing in a firstdirection, the first control panel having a first set of temperatureselectors corresponding to a first set of selected heating padtemperatures; and the power unit further comprises a side-facing secondcontrol panel facing in a second direction, the second control panelhaving a second set of temperature selectors corresponding to a secondset of selected heating pad temperatures.
 38. The heating pad system ofclaim 34 wherein: the control panel is a side-facing first control panelfacing in a first direction, the first control panel having a first setof temperature selectors corresponding to a first set of selectedheating pad temperatures; and wherein the power unit further comprises aside-facing second control panel facing in a second direction that isopposite to the first direction, the second control panel having asecond set of temperature selectors corresponding to a second set ofselected heating pad temperatures.
 39. The heating pad system of claim34 wherein: the control panel is a side-facing first control panelfacing in a first direction, the first control panel having a set oftemperature selectors corresponding to selected heating padtemperatures; and wherein the power unit further comprises a side-facingsecond control panel facing in a second direction opposite to the firstdirection, the second control panel having the set of temperatureselectors corresponding to the selected heating pad temperatures. 40.The heating pad system of claim 34 wherein the mobile support structurehas a bed portion suitable for the person to lay on, and wherein thepower unit is releasably attachable to the mobile support structure atleast partially disposed beneath at least a portion of the bed portion.41. The heating pad system of claim 34 wherein the power unit isoptionally connectable to an AC power source, wherein when the powerunit is connected to the AC power source the power unit can provideelectrical power to the thermal-electric heating element from the ACpower source.
 42. The heating pad system of claim 34 wherein the powerunit is optionally connectable to a 12-volt DC power source, whereinwhen the power unit is connected to the 12-volt DC power source thepower unit can provide electrical power to the thermal-electric heatingelement from the 12-volt DC power source.
 43. The heating pad system ofclaim 34 wherein: the power unit is optionally connectable to an ACpower source, wherein when the power unit is connected to the AC powersource the power unit can provide electrical power to thethermal-electric heating element from the AC power source; and whereinthe power unit is optionally connectable to a 12-volt DC power source,wherein when the power unit is connected to the 12-volt DC power sourcethe power unit can provide electrical power to the thermal-electricheating element from the 12-volt DC power source.
 44. The heating padsystem of claim 34 wherein: the heating pad further comprises awaterproof cover at least partially enclosing the lower foam pad, theupper foam pad, and the thermal-electric heating element; and whereinthe power unit provides electrical power to the thermal-electric heatingelement via a utility cord, the utility cord passing through an openingin the cover, the opening being hermetically sealed.
 45. The heating padsystem of claim 34 wherein the heating pad further comprises a sheet ofreflective material positioned adjacent to the lower foam pad such thatthe lower foam pad is disposed between the sheet of reflective materialand the thermal-electric heating element.
 46. The heating pad system ofclaim 34 wherein the upper foam pad has an upper surface, and whereinthe heating pad system further comprises: a first temperature sensor formeasuring heating pad temperatures, wherein at least a portion of thefirst temperature sensor is positioned adjacent to the upper surface ofthe upper foam pad, the first temperature sensor being operablyconnected to the power unit, and wherein the power unit includes atemperature control circuit coupled to the temperature sensor to controlelectrical power provided to the thermal-electric heating element basedon a selected heating pad temperature and a measured heating padtemperature; and a second temperature sensor for measuring heating padtemperatures, wherein at least a portion of the second temperaturesensor is positioned adjacent to the upper surface of the upper foampad, the second temperature sensor being operably connected to the powerunit, and wherein the power unit includes a temperature display fordisplaying measured heating pad temperatures received from the secondtemperature sensor.
 47. The heating pad system of claim 34 wherein theupper foam pad has an upper surface and the power unit includes atemperature display for displaying measured heating pad temperatures,and wherein the heating pad system further comprises: a temperaturesensor for measuring heating pad temperatures, wherein at least aportion of the temperature sensor is embedded in the upper foam padadjacent to the upper surface, the temperature sensor being operablyconnected to the power unit for providing measured heating padtemperatures to the temperature display.
 48. The heating pad system ofclaim 34 wherein: the upper foam pad is comprised of an ester-basedviscoelastic memory foam; the lower foam pad is comprised of a foamhaving an IFD rating of at least 30; the lower foam pad is comprised ofa foam having an IFD rating of no more than 40; and the thermal-electricheating element is comprised of a carbon-filled plastic having one ormore copper braids for conducting electrical current for generatingheat.
 49. The heating pad system of claim 34 wherein the control panelfurther includes a power-loss indicator for indicating a pre-selectedstatus of the power source.
 50. The heating pad system of claim 34wherein the control panel further includes a power-loss indicator forindicating a pre-selected status of the power source, the power-lossindicator being a visual indicator.
 51. The heating pad system of claim34 wherein the control panel further includes a power-loss indicator forindicating a pre-selected status of the power source, the power-lossindicator being a visible light source.
 52. The heating pad system ofclaim 34 wherein the control panel further includes a power-lossindicator for indicating a pre-selected status of the power source, thepower-loss indicator being a digital display.
 53. The heating pad systemof claim 34 wherein the control panel further includes a power-lossindicator for indicating a pre-selected status of the power source, thepower-loss indicator being an audio indicator.
 54. A heating padcomprising: a foam pad; a carbon-filled plastic thermal-electric heatingelement having one or more copper braids for generating heat, thethermal-electric heating element being disposed adjacent to the foampad; and a waterproof and flame-retardant cover enclosing at least aportion of the foam pad and the thermal-electric heating element. 55.The heating pad of claim 54 wherein the foam pad is an upper foam pad,and wherein the heating pad further comprises: a lower foam pad, thethermal-electric heating element being sandwiched between the upper andlower foam pads.
 56. The heating pad of claim 54 wherein the foam pad isan upper foam pad, and wherein the heating pad further comprises: alower foam pad, the upper foam pad being denser than the lower foam pad,the thermal-electric heating element being sandwiched between the upperand lower foam pads.
 57. The heating pad of claim 54 wherein the foampad is an upper foam pad comprised of a foam having an IFD ratingbetween 10 and 30 inclusive, and wherein the heating pad furthercomprises: a lower foam pad, the lower foam pad being comprised of afoam having an IFD rating of between 25 and 45 inclusive, thethermal-electric heating element being sandwiched between the upper andlower foam pads.
 58. The heating pad of claim 54 wherein the foam pad isan upper foam pad comprised of a foam having a density of between 3.5 to4.5 lb. per cubic foot inclusive, and wherein the heating pad furthercomprises: a lower foam pad, the lower foam pad being comprised of afoam having a density of between 2.0 to 3.0 lb. per cubic footinclusive, the thermal-electric heating element being sandwiched betweenthe upper and lower foam pads.
 59. The heating pad of claim 54, furthercomprising: a sheet of reflective material covering at least a portionof the thermal-electric heating element between the thermal-electricheating element and the foam pad.
 60. A method for warming a person on asupport structure such as a gurney or an operating room table, themethod comprising: providing a heating pad positionable on the supportstructure, the heating pad comprising: a thermal-electric heatingelement comprising one or more copper elements suspended in acarbon-filled plastic for conducting electricity; a foam pad disposedadjacent to the thermal-electric heating element, the foam padoverlaying at least a portion of the heating element, and a form-fittingwaterproof cover enclosing at least a portion of the foam pad and thethermal-electric heating element; positioning the heating pad on thesupport structure; positioning the person on the heating pad; andproviding electrical power to the thermal-electric heating element. 61.The method of claim 60 further comprising: providing a power unit forproviding electrical power to the thermal-electric heating element, thepower unit including a control panel having at least one temperatureselector, the temperature selector for selecting at least one heatingpad temperature.
 62. The method of claim 60 wherein the foam pad is anupper foam pad, the heating pad further comprising: a lower foam pad,the thermal-electric heating element being sandwiched between the upperfoam pad and the lower foam pad, the form-fitting waterproof coverenclosing at least a portion of the upper foam pad, the lower foam padand the thermal-electric heating element.
 63. The method of claim 60further comprising: providing a power unit for providing electricalpower to the thermal-electric heating element, the power unit includinga control panel having at least one temperature selector, thetemperature selector for selecting at least one heating pad temperature;and selecting a heating pad temperature using the at least onetemperature selector.